text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _FS_CEPH_MDSMAP_H
  #define _FS_CEPH_MDSMAP_H
  
  #include <linux/bug.h>
  #include <linux/ceph/types.h>
  
  /*
   * mds map - describe servers in the mds cluster.
   *
   * we limit fields to those the client actually xcares about
   */
  struct ceph_mds_info {
  	u64 global_id;
  	struct ceph_entity_addr addr;
  	s32 state;
  	int num_export_targets;
  	bool laggy;
  	u32 *export_targets;
  };
  
  struct ceph_mdsmap {
  	u32 m_epoch, m_client_epoch, m_last_failure;
  	u32 m_root;
  	u32 m_session_timeout;          /* seconds */
  	u32 m_session_autoclose;        /* seconds */
  	u64 m_max_file_size;
  	u32 m_max_mds;			/* expected up:active mds number */
  	u32 m_num_active_mds;		/* actual up:active mds number */
  	u32 possible_max_rank;		/* possible max rank index */
  	struct ceph_mds_info *m_info;
  
  	/* which object pools file data can be stored in */
  	int m_num_data_pg_pools;
  	u64 *m_data_pg_pools;
  	u64 m_cas_pg_pool;
  
  	bool m_enabled;
  	bool m_damaged;
  	int m_num_laggy;
  };
  
  static inline struct ceph_entity_addr *
  ceph_mdsmap_get_addr(struct ceph_mdsmap *m, int w)
  {
  	if (w >= m->possible_max_rank)
  		return NULL;
  	return &m->m_info[w].addr;
  }
  
  static inline int ceph_mdsmap_get_state(struct ceph_mdsmap *m, int w)
  {
  	BUG_ON(w < 0);
  	if (w >= m->possible_max_rank)
  		return CEPH_MDS_STATE_DNE;
  	return m->m_info[w].state;
  }
  
  static inline bool ceph_mdsmap_is_laggy(struct ceph_mdsmap *m, int w)
  {
  	if (w >= 0 && w < m->possible_max_rank)
  		return m->m_info[w].laggy;
  	return false;
  }
  
  extern int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m);
  extern struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end);
  extern void ceph_mdsmap_destroy(struct ceph_mdsmap *m);
  extern bool ceph_mdsmap_is_cluster_available(struct ceph_mdsmap *m);
  
  #endif
  